When neurologically normal individuals bisect a horizontal line as accurately as possible, they reliably show a slight leftward error. This leftward inaccuracy is called "pseudoneglect" because errors made by neurologically normal individuals are directionally opposite to those made by persons with visuospatial neglect (Jewell & McCourt, 2000). In…

Previous research in our laboratory has examined the distribution of preferred hand (PH) reaches in working space with right-handed participants. In one study, we examined the effects of tool position and task demands on the frequency of PH reaches with right-handers (Mamolo, Roy, Bryden, & Rohr, 2004). We found that PH reaches were at a maximum…

The handedness of Leonardo da Vinci is controversial. Although there is little doubt that many of his well-attributed drawings were drawn with the left hand, the hatch marks of the shading going downwards from left to right, it is not clear that he was a natural left-hander, there being some suggestion that he may have become left-handed as the…

This study examined whether children exposed to prenatal smoking show deficits in "hot" and/or "cool" executive functioning (EF). Hot EF is involved in regulation of affect and motivation, whereas cool EF is involved in handling abstract, decontextualized problems. Forty 7 to 9-year-old children (15 exposed to prenatal smoking, 25 non-exposed)…

Three experiments were carried out to investigate hemispheric asymmetry in color processing among normal participants. In Experiment 1, it was shown that the reaction times (RTs) of the dominant and non-dominant hands assessed using a visual target presented at the central visual field, were not significantly different. In Experiment 2, RTs of…

Photosensitivity or photoparoxysmal response (PPR) is a highly heritable electroencephalographic trait characterized by an abnormal cortical response to intermittent photic stimulation (IPS). In PPR-positive individuals, IPS induces spikes, spike-waves or intermittent slow waves. The PPR may be restricted to posterior visual areas (i.e. local PPR…

Background: Environmental risk during fetal development for non-right-handedness, an index of brain asymmetry, and its relevance for child mental health is not fully understood. Methods: A Swedish population-based prospective pregnancy-offspring cohort was followed-up when children were five years old (N = 1714). Prenatal environmental risk…

The purpose of the present study was twofold: first to examine the influences of sex and handedness on manual performance on the Grooved Pegboard Test; and secondly to provide normative data for two versions (Place and Remove tasks) of the Grooved Pegboard Test, as previous work (Bryden & Roy, 1999) had suggested that the Remove task of the…

The present study examined sleep architecture as a function of handedness in a population of undergraduate college women using a home sleep monitor. Compared to strongly handed individuals, participants with a tendency toward mixed-handedness had a shorter sleep latency and spent a greater percentage of their sleep period asleep and less awake.…

Performance-based measures of hand preference have been developed as an objective method of examining handedness. Previous research using this method by Bryden, Roy, and Mamolo (2003) showed that both skill demands and the position of the object in working space affect preferential hand reaching. Specifically, preferred hand reaches predominated…

Gottlieb used naturalistic observations of normally occurring events in the life history of individuals for the purpose of discovering the role of experience in the development of species-typical behaviors. His research revealed the impact of self-generated experiences (particularly those experiences that were self-stimulated) in the establishment…

The respective roles of the environment and innate talent have been a recurrent question for research into expertise. The authors investigated markers of talent, environment, and critical period for the acquisition of expert performance in chess. Argentinian chess players (N = 104), ranging from weak amateurs to grandmasters, completed a…

Magnetic resonance imaging was used to produce midsagittal images of the corpus callosum of 19 right-handed adult male and female subjects. The preliminary findings of this study indicate that significant adaptation in the anterior midbody of the corpus callosum has occurred to accommodate multiple language capacity in bilingual individuals…

This concise pamphlet describes methods of determining hand dominance in children. The pamphlet states that the child should be observed in certain procedures without being told that he or she is being tested. Among the test procedures suggested are activities with a hand puppet, hammering nails, and throwing a ball. The pamphlet offers directions…

This paper reviews the literature on handedness in infants and reaching behavior in neonates and speculates on evolutionary reasons for the development of handedness. Modern studies have reliably detected handedness from the second half of the first year of life. One study found a preference for the right hand in unimanual tasks at 6.7 months.…